Blended gasolines



June 7, 1960 PETER VA N'T SPIJKER ET AL FRACTIONATOR REGULAR 2 GASOLINE II l4 5 I a 5 I2 I3 I I5 HIGH OCTANE CATALYTIC REFORMING GASOLINE A CHAMBER FRACTIONATOR POLYMERIZATION CHAMBER l6 9 I8 I |7 A R CATALYTIC FRACTION TO CRACKING CHAMBER 7 20 I /FLASH CHAMBER FIG. I

mvemoas:

PETER VAN 'T SPIJKER EDUAR SWEEP BY:

THEIR ATTORNEY nitecl States BLENDED GASOLINES Peter Vant Spijker, The Hague, and Eduard Sweep,

Amsterdam, Netherlands, assignors to Shell Oil Company, a corporation of Delaware This invention relates to a process for the preparation of high octane gasoline.

There has been a tendency in recent years toward the use of increasingly high compression ratios in automobile gasoline engines. These engines require gasolines of ever higher octane numbers. The problem is continually present therefore of how to obtain these octane numbers using existing facilities and raw materials. One avenue of approach has been the addition of variouscompounds, e.g. metallo-organic compounds such as tetraethyl lead, which, when added to gasoline, have the eifect of raising its octane number. However, these compounds are expensive, and, moreover, only a limited amount of a compound of this type can be added to gasoline before it begins to have a harmful influence on the operation of the engine. Thus, in view of the limited amount of tetraethyl lead which can be added, the leaded octane number of a gasoline depends to a large extent on the octane number of the base stock to which the tetraethyl lead is added.

Much of the gasoline used in internal combustion engines at the present time is obtained by means of a process of the type known as catalytic reforming which is a complex conversion process utilizing low octane straight-run naphtha as a starting material. One of the more widely used processes of this type is that known as platforming in which the catalyst comprises 0.1 to 1% or preferably .3 to .8% by weight of platinum supported on alumina and may also contain a small amount of a halogen such as fluorine. The products resulting from this process as it is now generally carried out, however, do not appear to be completely satisfactory for the high compression automobile engi'nes which'are coming into use at the present time. This is especially true when the straight-run naphtha is obtained from a paratfin base crude oil. Moreover, the product obtained from a platforming process often does not satisfy minimum volatility requirements.

The octane numbers of the products obtained from reforming may usually be raised by running the process under more drastic conditions of temperature and pressure. However, this is to be avoided since it results in higher gas formation and shorter catalyst life.

It is an object of this invention to provide a process of producing gasolineof desired octane number utilizing a conventional reformate obtained by means of a reforming process utilizing a catalyst comprising platinum, without appreciably raising .the gas formation rate or shortening the catalyst life in the reforming process.

It has been found that a satisfactory high octane gasoline may be obtained by blending a heavy fraction of a reformate obtained from a process utilizing a platinumcontaining catalyst, at least 75% by volume, based on the reformate fraction, of a light fraction of catalytically cracked gasoline, and a component consisting of a polymer of propene or of a butene, and/or an alkylate obtained from isobutane and propene, butcnes or pentenes or a mixture. ofany of these olefins. The fractions utilized are that part of the reformate boiling above 130 C.,

atent 2,939,832 Patented June 7, 1960 preferably above 132 C., and the part boiling up to C. of the catalytically cracked gasoline. The polymet or alkylate or a mixture of the two should have a boiling point within the gasoline range, preferably from 100 to C.

Although the lower cutting temperature used in separating the heavy reformate may be somewhat higher than 130 0., e.g., C., it is preferably kept to 132 C. for this purpose. In any case, it should not fall below 130 C.

Gasolines obtained by means of this process have unleaded research octane numbers of 95 or higher and are composed of at least 30% of components boiling below 100 C. If desired, the octane number of these gasolines may be further increased by adding a small amount of tetraethyl lead, e.g. about 1.5 ml. per US. gallon. Antioxidants or other gasoline additives may also be added.

This process is particularly important in the case of reformates obtained from crude oils containing at least 50% parafiinic hydrocarbons, e.g. those obtained from Middle East crude oils, since these reformates have comparatively low octane numbers. However, the process may efiectively be applied to reformates obtained from other sources.

As stated above, the catalytically cracked fraction is present in an amount at least 75 by volume of reformate fraction. The preferable ratio of fractions is such that 0.8 to 1.5- parts of catalytically cracked gasoline fraction is present per part-of heavy reformate fraction.

The polymer, alkylate, or mixture of the two is present in an amount under 20% by volume of the final product. Usually an amount 10 to 15% by volume of the final product is sufiicient for a satisfactory composition.

Compositions containing 30-50 parts by volume of heavy re-forrnate fraction, 50-40 parts by volume of light cracked gasoline fraction and 10-20 parts by volume of polymer and/or alkylate per 100 parts by volume of the total gasoline were generally found to be extremely satisfactory in all respects.

A small amount, e.g. 4-6% by weight, of butane may be added in order. to bring the vapor tension of the prodnot to the desired value.

In preparing the gasolines of this invention, a small amount of components of the reformate boiling below 130 C. in an amount not over 35% by volume of the heavy reformate fraction may be used without appreciably lowering the octane number of the final product.

In conjunction with the preparation of the high octane gasoline under this invention, a good quality regular motor gasoline may be obtained by mixing a light reformate fraction boiling below 130 C., or a portion thereof with a heavy fraction of catalytically cracked gasoline boiling above about 100-115 C. and with alight straight run distillate (so called straight run tops) which boils below 100 C. and is obtained in topping crude oil. As heavy cracked gasoline fraction, the material may be conveniently used which remains behind in the separation of the cracked gasoline tops maintained for the high octane gasolines to be prepared according to this invention. The ratio of light reformate and heavy catalytically cracked gasoline fraction is often close to 1:1 although considerable variation in the proportions is possible depending on the nature of the components. The proportion of straight-run tops in the final gasoline may be about 40% by volume. On the addition of about 115 -ml. of tetraethyl lead per US. gallon, the resulting gasoline may have a research octane number of 85, which satisfies the requirements of a good motor gasoline of regular grade. Other additives, e.g. anti-oxidants may also be added.

This invention is particularly useful in that it enables a crude oil to be worked up with the aid of catalytic rei forming and catalytic cracking in such a way as to obtain optimum amounts of gasoline of premium and regular grades.

The initial material can be worked up with particular advantage in the manner shown diagrammatically in the accompanying drawing, wherein the sole figure is a schematic flow plan of applicants process.

in the fractionatingzone 1, there are separated from the crude oil supplied at A a light fraction boiling up to approximately 100 C. (straight-run tops) and a naphtha fraction boiling up to approximately 180 C., to 200 C., which fractions are withdrawn via the lines 2 and 3, respectively, and also a kerosine fraction and light and heavy gas oil fractions which are drawn oif via the lines 4, S and 6, respectively, the remaining residue being led via line 7 to a flash zone 8. In this zone the residue supplied is split by flashing at reduced pressure into a socalled flashed distillate which is drawn ofi at the top via line 9, and a heavy residue (so-called short residue), which is drawn oil at the bottom via line 10.

The naphtha fraction flows via line 3 to the catalytic reforming zone 11, in which itis reformed in a known manner by means of a platinum-containing catalyst at elevated temperature and hydrogen pressure. The reformate obtained, which is led to the fractionatin-g zone 13 via line 12 is split in this zone into a light fraction boiling below approximately 130 C., and a heavy fraction boiling above approximately 130 C., which are drawn ofl' via the lines 14 and 15, respectively, 7

The flashed distillate obtained in the flash zone 8 is used as feed for the catalytic cracking zone 16', in which it is cracked in a manner well known in the art using a conventional cracking catalyst, e.g silica-alumina. The cracked gasoline and gas oil fractions are separated from the higher boiling components by means of fractionation of the liquid cracked product, and the gas oil fraction may, if desired, be recycled to the catalytic cracking zone. The cracked gasoline is led via line 17' to the fractionating zone 18in which itis split into a light fraction boilingup to approxmately 100 C. to 115 C., and a heavier fraction which is drawn olf via lines 19 and 20, respectively. 1

The butane-butylene fraction is separated by fractionation from the normally gaseous products formed at the same time in zone 16 during catalytic cracking, which fraction is then led via line 21 to the polymerization zone 22 in which the butylenes are polymerized in a conventional manner by means of a polymerization catalyst, e.g. a solid catalyst containingphosphoric acid, to a polymer gasoline predominantly boiling between 100 Cfand 130 C., and is drawn off via line 23. The unconverted butane leaves the polymerization zone via line 24.

The light cracked gasoline fraction from line 19, together with the heavy reformate fraction from line and the butylene polymers from line 23, are now worked up according to the invention to a motor gasoline with an octane number of 95 or more. The light reformate fraction separated in the fractionating zone 13, together with the heavy cracked gasoline fractiondrawn off from the fractionating zone 18.via line 20, and the straight-run tops which are separated from the starting oil in the fractionating zone 1 and drawn off via line 2 are worked up to a regular motor gasoline with anoc-tane number of at least approximately 80.

The butane or a part thereof which is drawn oflj from the polymerization zone may be used to increase the vapor tension of the high. octane gasoline produced under this o nd i des r ls h te he te l gasoline.

s Of s g butylene polymers, p ymcr Qt propylene or of mixtures of propyleneandbutylene, to-be prepared in a similar manner-,as acomponent in the .prep-. aration of the high octane motor gasolines according Q h v n qnl k ate may a aq eusediq p pose which may be prepared in a conventional manner by alkylating isobutane with propene and/or butenes and/ or pentenes in the presence of an alkylation catalyst such as sulfuric acid or hydrofluoric acid. If desired, mixtures of the said polymers and alkylates may also be used. In general, however, it is preferred to use polymers as they are cheaper and simpler to prepare than alkylate.

The process according to. the invention is further illustrated, below by means of a. number of examples. The efie ence to I -1,4 o tane. n mber and F11..5 octane number occurring therein signifies the F-1 octane number respectively before and after the addition of 1.5 ml. of tetra-ethyl lead per US. gallon.

' EXAMPLE I The starting material was a straight-run naphtha which boiled from 93 C. to 191 0., had a content of 59.5% by weight of paralfin hydrocarbons and was obtained from a Middle East oil. This naphtha, together with bydrogen-rich recycle gas from the process, was passed in an amount corresponding to 8 mol of hydrogen per mol of naphtha, at temperatures between 460 and 500 C. and a pressure of 40 atm., over a commercial platforming catalyst at a rate of 2.3 liters per liter of catalyst per hour.

After separation of the hydrogen-rich gas phase, a part of which was recycled to the process, the liquid platformate obtained was split in a fractionating column with 30 trays into 52.3% by weight of a light fraction boiling up to 132 C. and 47.7% by weight of a heavy fraction boiling above 132 C, i

The heavy platformate fraction thus obtained, of which the F-l-LS octane number was 102, was now mixed with the light fraction boiling up to 100- C., of a cracked gasoline obtained by catalytic cracking a flashed distillate derived from the same Middle East oil whichwas used to obtain the straight-run naphtha, with the aid of a fluidized silica-alumina catalyst. A polymer mixture was also added which was obtained by polymerizaiton of the butylenes from the C fraction of the cracked gases formed during catalytic cracking, which mixture was prepared in the usual way with the aid of a polymerization catalyst containing phosphoric acid. More than by volume of the polymer mixture boiled between 100 C. and 130 C.

These three components were mixed together in such ratios that two mixtures (a and b) were obtained with the compositions shown in Table 1 Butane in. the, proportion of 5.8%. by weight was also added tov the a mixture. The properties of the mixtures thus formed are, shown in Tablez.

Table 2 Mixture 1 a b Specific gra-vityldw; 0; 7602 0. 7510 ASTM distillation; 7 initial boiling point, 01.- 31 i 43 10%by; volume to. -O 53 61* 50% by volume to 123 1.13 by volume to 179 173 final-boiling pcmt 2 133 212 Percentage by volum cqmpon C; 37 42 Reid vapor; pressure (at F.) 0,464. 0; 4 0 F-l-O octanenumben, .96. 8 96. 3 F l1.5 octane'number; 99: 6 99.1

The products thus obtained, which had also a high stability towards gum formation, had the properties of a good quality high octane motor gasoline.

By mixing the light fraction, separated from the platformate and boiling below 132 C., with the portion of the catalytically cracked gasoline boiling above 100 C., and with the straight-run tops separated from the starting oil, in a ratio by volume of approximately 30:30:40, and adding approximately 6% by weight of butane, a mixture was obtained which had an F-1-1.5 octane number of approximately 84 and formed an excellent motor gasoline.

EXAMPLE II 46 parts by volume of a heavy platforrnate fraction prepared in the manner indicated in Example I were mixed with 14 parts by volume of the butylene polymers referred to in Example I and with 40 parts by volume of the fraction boiling up to 115 C. of a cracked gasoline obtained by catalytic cracking of a flashed distillate of a Middle East crude oil.

The mixture thus obtained had an F-l-O octane number of 97.8, an F-1-1.5 octane number of 100.0 and a content of 30% by volume of components boiling up to 100 C. and had the properties of a good quality highoctane gasoline.

EXAMPLE III The heavy platformate fraction boiling above 132 0., light cracked gasoline fraction and butylene polymers, referred to in Example I, with the additional use of a portion of the light platformate fraction boiling up to 132 C. which was obtained on splitting of the total reformate, was combined to form a mixture of the composition shown in Table 3:

By adding 4.4% by weight of butane, the Reid vapor tension (at 100 F.) of this mixture was increased to 0.62 atm.

The product thus obtained had an F-l-O octane number of 96.0 and an F-1-1.5 octane number of 99.5, and contained 47% by volume of components boiling up to 100 C. and formed high octane gasoline of excellent quality.

EXAMPLE IV The heavy platformate fraction and light cracked gasoline fraction, referred to in Example I, were mixed in a ratio of 32 parts by volume to 48 parts by volume with 20 parts by volume of an alkylate obtained by alkylating isobutane with butylenes with the aid of sulfuric acid as catalyst, 65% by volume of which alkylate boiled be-' tween 100 C. and 130 C.

The mixture thus formed had an F11.5 octane number of 98.8 and a content of approximately 35% by volume of components boiling up to 100 C., the Reid vapor tension (at 100 F.,) being 0.35 atm.; it formed an excellent high octane gasoline.

We claim as our invention:

1. An integrated process for the preparation of premium" grade and regul grade motor gasolines which comprises the steps (1) fractionating a crude petroleum oil to obtain at least a light straight-11in fraction boiling up to about C., and a straight-run naphtha fraction boiling up to about 200 C., (2) reforming said straight-run naphtha fraction using a catalyst comprised of platinum supported on alumina, (3) separating the resulting reformate into a light reformate fraction boiling up to about 130 C. and a heavy reformate fraction boiling above about 130 C., (4) separating a catalytically cracked gasoline into a light catalytically cracked fraction boiling up to about C. and a heavy catalytically cracked fraction boiling above about 115 C., (5) blending the light catalytically cracked fraction, the heavy reformate fraction, and a material boiling predominantly between approximately 100 and C. and selected rom the group consisting of (a) a polymer of an olefin selected from the group consisting of propene, butenes, and mixtures thereof, (b) an alkylate prepared from the alkylation of isobutane with an olefin selected from the group consisting of propene, butenes, pentenes, and mixtures thereof, and (0) mixtures of the polymer and the alkylate, said material being blended in an amount up to 20% by volume based on the premium grade gasoline, to produce a premium grade gasoline consisting essentially of said material, the light catalytically cracked fraction, and the heavy reformate fraction and having an unleaded ASTM Research Method octane number above about 95, and (6) blending at least a portion of the light reformate fraction, the heavy catalytically cracked fraction, and said light straight run fraction boiling up to about 100 C. to produce a regular grade gasoline having an unleaded ASTM Research Method octane number of at least about 80.

2. The procms of claim 1 wherein 0.8 to 1.5 parts by volume of the light cracked gasoline fraction are used per part by volume of the heavy reformate fraction in the premium gasoline.

3. The process of claim 1 wherein the reformate is obtained from a straight-run naphtha taken from a crude oil containing at least 50% parafiinic hydrocarbons.

4. The process according to claim 1 wherein the regular gasoline contains the light straight-run fraction in a concentration less than 40% by volume and the volume ratio of light reformate to the heavy catalytically cracked fraction in the regular" gasoline is about 1:1.

5. The process according to claim 1 wherein a portion of the light reformate fraction is added to the premium gasoline in an amount less than 35% by volume, based on the amount of the heavy reformate fraction present in the premium gasoline, and the premium gasoline contains at least 30% by volume of components boiling below 100 C.

References Cited in the file of this patent 

1. AN INTEGRATED PROCESS FOR THE PREPARATION OF "PREMIUM" GRADE AND "REGULAR" GRADE MOTOR GASOLINES WHICH COMPRISES THE STEPS (1) FRACTIONATING A CRUDE PETROLEUM OIL TO OBTAIN AT LEAST A LIGHT STRAIGHT-RUN FRACTION BOILING UP TO ABOUT 100* C., AND A STRAIGHT-RUN NAPHTHA FRACTION BOILING UP TO ABOUT 200* C., (2) REFORMING SAID STRAIGHT-RUN NAPHTHA FRACTION USING A CATALYST COMPRISED OF PLATINUM SUPPORTED ON ALUMINA, (3) SEPARATING THE RESULTING REFORMATE INTO A LIGHT REFORMATE FRACTION BOILING UP TO ABOUT 130* C. AND A HEAVY REFORMATE FRACTION BOILING ABOVE ABOUT 130* C., (4) SEPARATING A CATALYTICALLY CRACKED GASOLINE INTO A LIGHT CATALYTICALLY CRACKED FRACTION BOILING UP TO ABOUT 115* C. AND A HEAVY CATALYTICALLY CRACKED FRACTION BOILING ABOVE ABOUT 115* C., (5) BLENDING THE LIGHT CATALYTICALLY CRACKED FRACTION, THE HEAVY REFORMATE FRACTION, AND A MATERIAL BOILING PREDOMINANTLY BETWEEN APPROXIMATELY 100* AND 130* C. AND SELECTED FROM THE GROUP CONSISTING OF (A) A POLYMER OF AN OLEFIN SELECTED FROM THE GROUP CONSISTING OF PROPENE, BUTENES, AND MIXTURES THEREOF, (B) AN ALKYLATE PREPARED FROM THE ALKYLATION OF ISOBUTANE WITH AN OLEFIN SELECTED FROM THE GROUP CONSISTING OF PROPENE, BUTENES, PENTENES, AND MIX- 